1. Field of Invention
The present invention relates to servo track writing for a magnetic storage device, and in particular, to a method for recording the port number of a servo track writer on a predetermined area of a disk surface for efficient management of a manufacturing process of a magnetic storage device.
2. Description of the Related Art
Magnetic storage devices such as a hard disk drive and a floppy disk drive are widely used as auxiliary memory devices for a computer system. In particular, the hard disk drive has the advantages of stable storage of massive data and high-speed data access.
U.S. Pat. No. 5,272,578 to Diau entitled Method For Writing A Uniform Servo Code Into A Magnetic Disk Drive discloses a method for writing a final track positioning servo code into a servo code signal region of a set of disks of a magnetic disk drive. U.S. Pat. No. 5,381,281 to Shrinkle et al. entitled Disk Drive System Using Multiple Embedded Quadrature Servo Fields disclose a quadrature based embedded servo control system wherein each data sector includes a gray code field spanning the entire width of the data track and a quad-servo burst pattern having first, second, third, and fourth servo burst fields distributed along the length of a portion of the data sector, with the center point of the first, second, third, and fourth servo bursts being sequentially offset from the adjacent burst by a radial distance equivalent to one-half of the data track width. It is further disclosed that a second gray code field extending substantially the width of the data track and a second quad-servo burst pattern substantially identical to the first is provided near a mid-point in the data portion of the data sector. A servo pattern is disclosed for providing servo information for the positioning of a head with respect to concentric data tracks provided on the surface of a data storage media, wherein each data track includes a series of data sectors, with the servo pattern including a plurality of servo burst fields provided in each data sector and in a series ordered along the length of each data sector.
U.S. Pat. No. 5,390,324 to Burckhartt et al. entitled Computer Failure Recovery And Alert System disclose a computer system including a timer which times out if the operating system of the computer system does not periodically reset the timer. It is disclosed the computer performs its power on program and checks the memory array for bad memory blocks, which are mapped out of the memory, with the computer system alerting the operator of the failure using a pager. U.S. Pat. No. 5,500,848 to Best et al. entitled Sector, Servo Data Recording Disk Having Data Regions Without Identification (ID) Fields disclose a data recording disk file with a fixed block architecture sector format that eliminates the ID region. It is disclosed the servo region contains sector identification information in the form of a start-of-track indicating mark recorded in a selected sector of each track and a start-of-sector indicating mark recorded in each sector, with a full track number identifier being encoded in the position field within the servo region of each sector. It is disclosed a look-up table is built at format time to map bad sectors out of the disk file. U.S. Pat. No. 5,519,546 to Lewis entitled Apparatus For, And Methods Of, Recording Signals In Tracks On A Memory Member Without Using Reference Indices Such As Clock Signals discloses a head records a track (e.g. a servo track) in a memory member outside of a clean room without using reference indices, wherein in each of a plurality of cyclical movements (e.g. revolutions), signals (e.g. servo signals) are recorded in the track in an individual number of frames. It is disclosed that sectors and data sectors following the sectors are recorded with signals in progressive cyclical movements in an embodiment.
U.S. Pat. No. 5,566,339 to Perholtz et al. entitled System And Method For Monitoring Computer Environment And Operation disclose an advanced electronic alert system for monitoring computer network(s), environment, security and the status of tasks being processed by a computer. A mass storage device associated with a computer is disclosed with data interface means connected to control means and the computer for connecting a monitoring apparatus to the computer to transfer data between the monitoring apparatus and the mass storage device associated with the computer in response to signals received from the control means.
U.S. Pat. No. 5, 581,606 to Gineys entitled Data Storage Back-Up And Modem Apparatus discloses a streamer apparatus for transferring data between a first storage device of a computer system, which has serial interface transmit and receive ports for transmitting and receiving data and a digital audio storage device, which has audio input and output lines. U.S. Pat. No. 5,596,711 to Burckhartt et al. entitled Computer Failure Recovery And Alert System disclose a computer system which includes a timer which times out if the operating system of the computer system does not periodically reset the timer. It is disclosed the computer system performs its power on program and checks the memory array for bad memory blocks, which are mapped out of the memory. It is also disclosed the computer system alerts the operator of the failure using a pager.
U.S. Pat. No. 5,619,387 to Ottesen et al. entitled Disk Storage Device With Spiral Data Track And Incremental Error Offsets In Angularly Spaced Imbedded Concentric Servo Patterns disclose a disk drive which stores multimedia data in long spiral data tracks, wherein the tracks on opposite surfaces of the disk spiral in opposite directions, so that a track on one surface can be read as the actuator sweeps in, and a track on the opposite surface can be read as the actuator sweeps out. Servo sectors are disclosed as written to the disk in a conventional concentric manner, rather than using a spiral pattern wherein, when writing servo sectors, a circular track of sectors is written around the disk, and at an index position the servo writer increments its location by one track width to write the next circular track concentric with the first, successively writing servo tracks in this manner until the disk surface is completely traversed. U.S. Pat. No. 5,706,145 to Hindman et al. entitled Apparatus And Methods For Audio Tape Indexing With Data Signals Recorded In The Guard Band disclose apparatus and methods for providing an indexed audio tape, wherein the method includes the step of recording data in a guard band interposed between and parallel to two signal tracks used to record audio signals on an audio tape.
U.S. Pat. No. 5,710,677 to Teng et al. entitled Method of Detecting And Isolating Defective Servo Bursts disclose a method to determine a defective servo burst written on a recording medium having a plurality of tracks, each track containing a plurality of position data portions, wherein the position data portions include servo bursts capable of providing position error information, which can be selectively retrieved by a servo control system having a servo gate enabling signal. U.S. Pat. No. 5,715,105 to Katayama et al. entitled Method Of And Apparatus For Recording On And Reproducing From Disk-Type Recording Medium Having Recording Tracks With Sectors Each Having An ID Area And A Data Area disclose a magnetic disk recording and reproducing apparatus including a unit for inserting an error correcting code relating to control information in the control information, the control information relating to data, a recording control unit for recording the control information and the data in a recording area of a magnetic disk, the recording area having a plurality of sectors. It is disclosed that each of the sectors having an ID area for recording the control information and a data area for recording the data, the data area corresponding to the ID area and being provided adjacent to and behind the ID area in the same sector as the ID area, and an error correcting unit for correcting errors in the control information in the ID area using the error correcting code before the data in the data area corresponding to the ID area and provided in the same sector as the ID area is read or recorded.
U.S. Pat. No. 5,719,721 to Iizuka et al. entitled Method And Apparatus For Recording Track Numbers In A Standard Recording Mode And A Long Time Recording Mode disclose that when a ratio of track pitches in an SP mode and an LP mode is equal to 3:2 the track number is recorded onto each track by advancing the track number one by one in the SP mode and the track number is advanced by setting the even or odd track numbers as a same track number in two tracks and is recorded onto each track in the LP mode. It is disclosed that even when a new recording is performed onto a recorded tape, the track numbers are continuous, so that the track number can be used for detecting the absolute address. U.S. Pat. No. 5,745,453 to Ikeda entitled Disk, Recording Device, Reproducing Device, Recording Method And Reproducing Method Including Calculation, Storage And Utilization of Parity Information discloses a disk for recording specified data having a plurality of helically formed track areas with one round of the circumferential direction of the disk as one track and a plurality of sector areas in which the plurality of track areas given track numbers added continuously from the outer peripheral direction of the disk are dividedly formed. It is disclosed that the plurality of sector areas include a plurality of data areas for storing the specified data and one parity sector for storing the parity of the specified data stored therein, wherein the plurality of sector areas are given sector numbers added continuously from the starting positions of the track areas. It is disclosed that in an information recording block having the plurality of sector areas included in the specified number of ones of the plurality of track areas, a plurality of parities recorded in the parity sector areas of these track areas are calculated by using different track and sector numbers.
In general, a hard disk drive includes a disk for rapidly rotating by an internal spindle motor, and an actuator arm having a magnetic head for recording or reading data on or from a track of the disk. The actuator arm, installed to rotate around a pivot shaft, has a bobbin and a coil in an end portion thereof. The bobbin and the coil are moved by operation of a voice coil motor, and the magnetic head attached at the tip of a suspension in the other end portion of the actuator arm moves between both ends of the disk, to record or read data on or from a track of the disk. The magnetic head moves over the disk at a very small levitation height due to an air flow generated by high-speed rotation of the disk.
Further, in a disk assembly, having bands on the disk installed around a driving shaft of the spindle motor, the disk is divided into a parking zone where the head is positioned when the drive is not used, that is, when the power is off, a data band where data is recorded, an outer guard band, and an inner guard band. In order to write and read data on and from the data band, a servo control is required to move the magnetic head to a target track and make the magnetic head follow a center line of the target track within a predetermined range. For servo control in a hard disk drive, servo information should be recorded on the disk. The servo information is generally recorded on the disk by a servo track writer during a manufacturing process of the hard disk drive.
Sector formats for tracks are concentrically arranged in the data band of the disk. A servo sector and a data sector are alternately arranged in a track. The data sector is divided into a data identification region (absent in a headerless format) for recording data identification information, and a data region for recording user data. The servo sector is divided into auto gain control, servo synchronization signal, servo address mark, index, gray code, servo burst (A, B, C, and D), and PAD regions. The auto gain control keeps the time required for shifting the magnetic head from a data writing state to a servo information reading state and the magnitude of a position signal read by the magnetic head constant all over the disk regions. The servo synchronization signal provides synchronization for servo signal detection, the servo address mark provides reference signals for generating various servo timings, and the index provides information on one rotation of a disk. The servo bursts serve to control an on-track position of a head. In the gray code, address information such as servo sector, head, and cylinder numbers is recorded.
However, the servo sector does not reveal what servo track writer was used in a manufacturing process of a hard disk drive, though it includes many pieces of servo information. Such servo track writer information, if it is recorded along with servo information, is useful in managing the numbers of daily products, good products, and bad products. In addition, when the servo information is wrongly recorded, the servo track writer information enables a corresponding servo track writer to be easily detected, and efficiently repaired and maintained. However, since the port numbers of servo track writers are not recorded in a conventional manufacturing process of a hard disk drive, it cannot be easily determined in an failure analysis which servo track writer was used, although a port number is given to an individual servo track writer. As a result, due to the absence of servo track writer port numbers, a substantial amount of time and effort is required to detect, repair, and maintain a corresponding servo track writer when servo information is wrongly recorded during the conventional servo track writing process for a hard disk drive, and an operator manually calculates the number of daily products, good products, and bad products for process management.